Machine tool

ABSTRACT

A machine tool having a gate-type construction and provided with a tool magazine (11). The tool magazine (11) is mounted between a pair of support portions (3a) of a gate-shaped column (3) and above a work support table (2). The tool magazine (11) is composed of a plurality of tool holders (16) each holding a tool (17), and a driving device (18) for moving the tool holders (16) back and forth. This arrangement permits an efficient use of the working space on the work support table (2), and makes it possible to reduce the sizes of the support table (2) and a bed (1).

TECHNICAL FIELD

The present invention relates to a machine tool and, more particularly,to a machine tool having a gate-type construction, provided with animproved tool magazine.

BACKGROUND ART

Such a machine tool is known already as having a support table mountinga workpiece and carrying a tool magazine from which necessary tools aretaken out successively to effect various machinings in sequence. In theknown machine tool of the kind described, as shown, for example, in thespecification of U.S. Pat. No. 3,709,623, the tool magazine is placed atone end of the support table so as not to hinder the machining of theworkpiece, so that the support table is made to travel a distancegreater than the stroke necessary for the ordinary machining, when thetool is replaced. In consequence, the working space on the support tableis undesirably limited by the installation of the tool magazine. Thesize of the support table also has to be increased to require largersizes of devices such as bed, table feed device and so forth.

DISCLOSURE OF THE INVENTION

Under this circumstance, the present invention aims as its object atproviding a gate-type machine tool in which the working space on thesupport table is not limited and in which the stroke of the supporttable is reduced to permit a reduction in the sizes of the support tableand the bed, thereby to overcome the above-described problems of theprior art. To this end, according to the invention, there is provided amachine tool comprising: a bed; a gate-shaped column straddling a worksupport table; a spindle mounted on a cross-slide portion of thegate-shaped column and rotatable around a vertical axis; said spindlebeing movable in the vertical direction toward and away from the worksupport table and slidable horizontally perpendicularly to the directionof up and downward movement; wherein the improvement comprises a toolmagazine mounted between the support portions of the gate-shaped columnand above the work support table, the tool magazine including toolholders adapted to hold the tools of the tool magazine such that theaxes of the tools are arranged to extend in the vertical direction andto be in parallel alignment with the sliding direction of the spindle,and a driving device for driving the tool holder in the directionperpendicular to the directions of vertical movement and horizontalsliding of the spindle thereby to bring the tool between a toolmounting/demounting position where the tool aligns with the slideposition of the spindle and a position where the tool does not interferewith the spindle.

As stated above, according to the invention, a tool magazine is mountedbetween the support portions of the gate-shaped column, so that it ispossible to make efficient use of the working space on the work supporttable and to eliminate unnecessary stroke of the work support table. Inconsequence, the size of the work support table, as well as the size ofthe bed, can be reduced advantageously.

Furthermore, since the tools on the tool magazine are arranged such thattheir axes extend in the vertical direction and are in parallelalignment with the direction of sliding of the spindle, it is possibleto bring the necessary tool into axial alignment with the spindle bymaking use of the horizontal sliding movement of the spindle, and tomake the mounting and demounting of the tool by making use of thevertical movement of the spindle. It is, therefore, possible to effect achange of the tool without fail by a simple construction.

In the second and third embodiments, the tool holders are mountedshiftably so that it is possible to store and use a larger number oftools even when the slide stroke of the spindle is small. Particularly,in the third embodiment of the invention, it is possible to makepreparatory arrangements of the tool magazine during the machining.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a first embodiment of theinvention;

FIG. 2 is an elevational view of the embodiment shown in FIG. 1 asviewed in the direction of an arrow II;

FIG. 3 is an enlarged sectional view taken along the line III--III ofFIG. 2;

FIG. 4 is a side elevational view of a second embodiment of theinvention;

FIG. 5 is an enlarged view of a portion indicated by an arrow V in FIG.4;

FIG. 6 is a sectional view taken along the line VI--VI of FIG. 5;

FIG. 7 is an illustration of a third embodiment of the invention,corresponding to the portion indicated by the arrow V in FIG. 4; and

FIG. 8 is a sectional view taken along the line VIII--VIII of FIG. 7.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the invention will be described hereinunderwith reference to the accompanying drawings. FIGS. 1 thru 3 show a firstembodiment, FIGS. 4 thru 6 show a second embodiment and FIGS. 7 and 8show a third embodiment of the invention.

The first embodiment of the invention will be described hereinunder withreference to FIGS. 1 thru 3. A reference numeral 1 denotes a bed, 2denotes a support table movably mounted on the bed 1 for supporting aworkpiece W, 3 denotes a gate-shaped column mounted on the bed 1 bymeans of support portions 3a so as to straddle the support table 2, 4designates a slide table mounted on a cross-slide portion 3b of thecolumn 3 to be slidable in a horizontal direction, 5 denotes avertically movable table mounted on the table 4 for free movement in theup and downward directions, and 6 denotes a spindle head integral withthe vertically movable table 5. The spindle head 6 carries a spindle 7which is rotatable around a vertical axis. A reference numeral 8designates a feed motor mounted on the cross-slide 3b of the column 3and adapted to feed the slide table 4 in the horizontal direction, 9denotes a motor mounted on the slide table 4 and adapted to drive thevertically movable table 5 in the up and down directions, and numeral 10designates a spindle driving motor provided on the spindle head 6.

In the machine tool of the embodiment having the gate-shaped column 3, atool magazine 11 is installed between the left and right supportportions 3a of the column 3 and above the support table 2. Namely, asupport bracket 12 is fixed between the left and right support portions3a. A pair of guide rods 13 fixed to the support bracket 12 has axeswhich extend in the front and rear directions perpendicular to thedirections of the vertical movement of the spindle head 6 and thesliding movement of the slide table 4. The guide rods 13 movably carry aframe 14 to guide the later. The frame 14 is connected to a drivingcylinder 18. A supporting member 15 parallel to the sliding direction ofthe slide table 4 is fixed to the front end of the frame 14. A pluralityof tool holders 16 for clamping and holding the tools 17 are arrayed atregular intervals on the supporting member 15.

Referring now to FIGS. 4 to 6 showing the second embodiment of theinvention, the tool magazine 11 includes, in place of the supportingmember 15 of the first embodiment fixed to the front end of the frame14, a guide member 20 which is parallel to the direction of slidingmovement of the slide table 4. The guide member 20 has a guide groove 21which slidably receives and guides a slider 22 on which arrayed are aplurality of tool holders 16. An engaging shaft 23 is formed to protrudefrom the substantially central portion of the upper surface of theslider 22. An engaging member 25 is fixed to the piston rod end of acylinder device 24 fixed to the column 3. The engaging member 25 has aslot which extends in parallel with the axis of the guide rod 13 and isadapted to be engaged by the aforementioned engaging shaft 23, so thatthe slider 22 is shiftable along the guide member 20.

In the third embodiment shown in FIGS. 7 and 8, the tool magazine 11 hasa movable guide member 20 fixed to the front end of the frame 14, and apair of stationary guide members 20a, 20b fixed to the left and rightsupports of the column 3. Two sets of sliders 22a, 22b of lengths withinthe span of the movable guide member 20 are arranged such that one ofthese two sets is shiftably guided by the movable guide member 20, whilethe other is shiftably guided by one of the stationary guide members20a, 20b. Needless to say, a multiplicity of tool holders 16 are arrayedon each slider 22a, 22b.

The sliders 22a, 22b have engaging shafts 23a, 23b projected from thesubstantially central portions of the sliders 22a, 22b. The engagingmember 25 has a bifurcated form and is provided with a pair of engagingportions 25a, 25b formed on both legs thereof. Slots are formed in theseengaging portions 25a, 25b so as to extend in parallel with the axis ofthe guide rod 13, and are engaged by the aforementioned engaging shafts23a, 23b. The piston rod end of the shifting cylinder device 24 fixed tothe column 3 is connected to a substantially central portion of theengaging member 25. A rod 26 fixed to the column 3 guides and supportsthe engaging member 25.

An explanation will be made hereinunder as to the operation of eachembodiment. Referring first to the first embodiment, the machine tool isshown in FIG. 1 in the initial state in which the tool magazine 11 hasbeen fully retracted, i.e. in the state in which the frame 14 has beenretracted by the driving cylinder 18. For returning a tool 17 after theuse on the spindle 7 to the tool magazine 11, the spindle head 6 islowered vertically as viewed in FIG. 2, and is then moved to the left orright to position the spindle 7 ahead of the vacant tool holder 16. Theframe 14 is moved ahead in this state to make the vacant tool holder 16clamp the tool 17 on the spindle 7. Then, a known tool clamper (notshown) in the spindle 7 is operated to unclamp and release the tool 17.Then, the spindle 7 is moved vertically upwardly, so that the tool 17 iswithdrawn from the spindle 7 while being clamped and held by the toolholder 16. The spindle 7 which has been moved to the uppermost positionin its vertical stroke is then slided to the position just above thetool holder 16 holding the necessary tool 17, and is then lowered tomount the tool 17. Then, the known tool clamper in the spindle 7 isoperated to clamp the tool 17. Thereafter, the frame 14 is retracted toa position where the tool magazine 11 does not interfere with themachining of the workpiece W. Meanwhile, the spindle 7 is lowered in thevertical direction to commence the machining of the workpiece W.

In the second embodiment, the back and forth movement to the toolmagazine 11 and the vertical movement of the spindle 7 for changing thetool are performed in the same manner as the first embodiment. Thesecond embodiment can suitably be applied to the case where it isnecessary to mount a greater number of tools 17 within a limited slidestroke of the spindle 7. Namely, the slider 22 carries a multiplicity oftool holders 16 for holding greater number of tools 17 than in the firstembodiment. Therefore, within a given sliding stroke of the spindle 7,it is not possible to attach the tools located at both end regions. Inthis second embodiment, however, the shifting cylinder device 24 isoperated to shift the slider 22 to the left or right when the toolmagazine has been fully retracted, thereby to permit the attaching anddetaching of the tools in the both end regions within the given slidestroke of the spindle 7. In this second embodiment, it is possible toobtain a greater range 19 of exchange of tool than the range 19 in thefirst embodiment.

In the third embodiment, although the range 19 of tool exchange islimited to the range of slide stroke of the spindle 7, it is possible tostore and use a greater number of tools 17 than the second embodimentthanks to the use of two sets of sliders 22a, 22b. In addition, for thesame reason, it is possible to make preparatory arrangements of the toolmagazine 11 even during the machining of the workpiece W. Namely, in theillustrated state, the sliders 22a, 22b are situated on the movableguide member 20 and the right stationary guide member 20b. Therefore,when the tool 17 necessary for the next machining is stored in the rightstationary guide member 20b, the shifting cylinder device 24 isactivated, in the state where the movable guide member 20 is in theretracted position, to shift the slider 22a from the movable guidemember 20 to the vacant stationary guide member 20a, while the slider22b is shifted from the right stationary guide member 20b to the movableguide member 20 thereby to accomplish the exchange of the two sets ofsliders 22a, 22b. It is also possible to replace the slider on the leftor right stationary guide members 20a, 20b with another slider preparedat the outside of the machine tool and carrying different tools.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, thepresent invention may be practiced otherwise than as specificallydescribed herein.

What is claimed is:
 1. A machine tool for machining a workpiececomprising:a bed; a workpiece support table slidably mounted on said bedfor movement in a first horizontal direction; a gate-shaped columnhaving a pair of upstanding support portions fixedly mounted on saidbed, said upstanding support portions being spaced in a secondhorizontal direction transverse to said first horizontal direction forpermitting said workpiece support table to move thereacross; a toolspindle mounted on said column for movements in a vertical direction aswell as in said second horizontal direction; and a tool magazine forremovably storing a plurality of tools, wherein said tool magazine isdisposed between said upstanding support portions and over saidworkpiece support table, and that said tool magazine comprises a supportbracket disposed between and secured to said support portions of saidcolumn and formed with a guide way extending in said first horizontaldirection, a frame mounted on said support bracket and slidable alongsaid guide way, linear tool support means provided on said frame forremovably holding a plurality of tools in such a manner that said toolsform a row extending in said second horizontal direction with the axesthereof extending in a vertical direction, and drive means connected tosaid frame for moving said tool support means between an advancedposition where the row of said tools is presented under said toolspindle for a tool change operation and a retracted position where saidrow of said tools do not interfere with the machining of said workpiece,wherein said tool support means includes a supporting member secured tosaid frame, a slider slidably supported by said supporting member insaid second horizontal direction, and a plurality of tool holdersmounted on said slider each for releasably holding one of said tools,and wherein said tool magazine further comprises shifting drive meansfixed to said column and connecting means provided between said shiftingdrive means and said slider for shifting said slider in said secondhorizontal direction when said shifting drive means is operated.
 2. Amachine tool as claimed in claim 1, wherein said connecting meanscomprises an engaging shaft fixed to said slider and an engaging memberfixed to said shifting drive means, said engaging member being providedwith a slot extending in said first horizontal direction and engageablewith said engaging shaft.
 3. A machine tool for machining a workpiececomprising:a bed; a workpiece support table slidably mounted on said bedfor movement in a first horizontal direction; a gate-shaped columnhaving a pair of upstanding support portions fixedly mounted on saidbed, said upstanding support portions being spaced in a secondhorizontal direction transverse to said first horizontal direction forpermitting said workpiece support table to move thereacross; a toolspindle mounted on said column for movements in a vertical direction aswell as in said second horizontal direction; and a tool magazine forremovably storing a plurality of tools, wherein said tool magazine isdisposed between said upstanding support portions and over saidworkpiece support table, and that said tool magazine comprises a supportbracket disposed between and secured to said support portions of saidcolumn and formed with a guide way extending in said first horizontaldirection, a frame mounted on said support bracket and slidable alongsaid guide way, linear tool support means provided on said frame forremovably holding a plurality of tools in such a manner that said toolsform a row extending in said second horizontal direction with the axesthereof extending in a vertical direction, and drive means connected tosaid frame for moving said tool support means between an advancedposition where the row of said tools is presented under said toolspindle for a tool change operation and a retracted position where saidrow of said tools do not interfere with the machining of said workpiece,wherein said tool support means includes a supporting member secured tosaid frame, a pair of sliders serially disposed and shiftable in saidsecond horizontal direction for selective support by said supportingmember, and a plurality of tool holders mounted on each of said sliderseach for releasably holding one of said tools in a row extending in saidsecond horizontal direction, and wherein said tool magazine furthercomprises a pair of stationary guide members fixed to said upstandingsupport portions, each for supporting a corresponding one of saidsliders while the other of said sliders is supported by said supportingmember, shifting drive means fixed to said column, and connecting meansprovided between said shifting drive means and said pair of sliders forshifting said pair of sliders simultaneously in said second horizontaldirection when said shifting drive means is operated, whereby one ofsaid sliders is shifted from said supporting member to one of saidstationary guide members while the other of said sliders is shifted fromthe other of said stationary guide members to said supporting member. 4.A machine tool as claimed in claim 3, wherein said connecting meanscomprises a pair of engaging shafts respectively fixed to said pair ofsliders, and an engaging member fixed to said shifting drive means andprovided with slots extending in said first horizontal direction andrespectively engageable with said engaging shafts.